CA2490860A1 - Real-time calibration scheduling method and algorithm for amoled displays - Google Patents

Real-time calibration scheduling method and algorithm for amoled displays Download PDF

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Publication number
CA2490860A1
CA2490860A1 CA002490860A CA2490860A CA2490860A1 CA 2490860 A1 CA2490860 A1 CA 2490860A1 CA 002490860 A CA002490860 A CA 002490860A CA 2490860 A CA2490860 A CA 2490860A CA 2490860 A1 CA2490860 A1 CA 2490860A1
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CA
Canada
Prior art keywords
pixels
calibration
algorithm
programming
scheduling method
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
CA002490860A
Other languages
French (fr)
Inventor
Servati Peyman
Nathan Arokia
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ignis Innovation Inc
Original Assignee
Ignis Innovation Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ignis Innovation Inc filed Critical Ignis Innovation Inc
Priority to CA002490860A priority Critical patent/CA2490860A1/en
Priority claimed from PCT/CA2005/001897 external-priority patent/WO2006063448A1/en
Priority claimed from CA002590366A external-priority patent/CA2590366C/en
Publication of CA2490860A1 publication Critical patent/CA2490860A1/en
Priority claimed from US14/253,422 external-priority patent/US9275579B2/en
Priority claimed from US14/261,755 external-priority patent/US9280933B2/en
Priority claimed from US14/738,393 external-priority patent/US10012678B2/en
Priority claimed from US14/816,817 external-priority patent/US10013907B2/en
Application status is Abandoned legal-status Critical

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Classifications

    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • G09G3/3225Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00Control of display operating conditions
    • G09G2320/02Improving the quality of display appearance
    • G09G2320/0285Improving the quality of display appearance using tables for spatial correction of display data
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00Control of display operating conditions
    • G09G2320/02Improving the quality of display appearance
    • G09G2320/029Improving the quality of display appearance by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
    • G09G2320/0295Improving the quality of display appearance by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel by monitoring each display pixel
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00Control of display operating conditions
    • G09G2320/04Maintaining the quality of display appearance
    • G09G2320/043Preventing or counteracting the effects of ageing

Abstract

This invention presents a scheduling method and algorithm for calibration of pixels in active-matrix organic light-emitting diode (AMOLED) displays. The pixels are calibrated based on their aging and usage during the normal operation of active matrix display. The display data is used to determine the pixels with high brightness for calibration, which guarantees high speed and accurate calibration. This method can be used with any current programmed pixels, in particular, current mirror based designs.

Description

Real-Time Calibration Scheduling Method and Algorithm for AMOLED Displays PRIOR ART
Methods for data line voltage measurement for passive pixels are presented for precharge purposes [1]. However, they do not provide the accuracy needed for active matrix, and after precharge, current programming must be performed. In addition, current-programming of current-driven pixels is slow due to parasitic line capacitances and suffers from non-uniformity for large displays. In particular, the speed is a major issue when programming with small currents.
PRESENT INVENTION
The present invention discloses a method for calibration of pixels at high brightness to achieve the high speed and accuracy that is needed in large or small area displays.
Voltage-programming is used for fast pixel programming. According to the disclosed calibration-scheduling algorithm herein, pixels with high brightness are selected. For these pixels, the pixel current is measured during voltage programming and the results are compared with the expected pixel current. The difference will be used to adjust the data voltage for programming of that pixel in future. Due to speed, accuracy, and ease of implementation, the applications of the disclosed technique ranges from electroluminescent devices used for cellphones, personal organizers, monitors, TVs, to large area display boards.
DESCRIPTION OF THE DRAWINGS
Figure 1 presents the proposed calibration-scheduling algorithm. A Linked List of pixels is generated in step 201. This Linked List is used to schedule the priority in calibration of different pixels. The number of pixels that are calibrated in each programming cycle is referred to as n and is found in step 202 based on the display size and shift in characteristics.
In step 203, n pixels are selected ("Selected Pixels") in the selected column from the beginning of the Linked List. To improve the accuracy and speed of calibration, we calibrate the pixels that must be programmed with currents higher than a threshold current ITH. Calibration at low currents is slow and often not accurate. In addition, maximum shift in characteristics happen for pixels with high current. The algorithm works also for !r,., = 0, where calibration is performed for all pixels irrespective of their programming current. In step 204, we enable "Calibration Model° for the "Selected Pixels" and "Normal Operation" for the rest of the pixels in the selected column. In step 205, all pixels in the selected column are programmed by a voltage source driver. For the "Selected Pixels° the current flowing through the data line is monitored during the programming cycle. in step 206, the monitored current is compared with the expected current that must flow through the data line, and a calibration data curve for the "Selected Pixels" is generated. The calibration data is used to boost programming voltage in the next programming cycles during the "Normal Operation". The "Selected Pixels° are calibrated and as a result are sent to the end of the linked List in step 207.
During display operation, the Linked List will provide a sorted list of pixels that must be calibrated.
This is performed by going back 208 to step 203 in the beginning of the next programming cycle.
This number n is determined based on the display size and expected instability in device characteristics with time. The total number of pixels N = 3.m~.m2, where m~
and m2 are the number of rows and columns in the display, respectively. The highest rate in characteristics shift is K (=~ll~t.l~. Each programming cycle takes t=1/f.m2. The maximum expected shift in characteristics after the entire display is calibrated is ~I11= K.f.Nln < e, where a is the allowed error. After this we can redo the calibration from the beginning and eliminate the error. This shows that n > K t.Nle or n > 3.K.m~lfe. For instance, if K =1 °~lhr, m~ =1024, f= 60 Hz, and a =
0.1 %, we have n > 0.14, which implies that we need to calibrate once in 5 programming cycles.
This is achievable with just one calibration unit, which operates only one time in 5 programming cycles. If we want a = 0.01 %, we have n > 1.4. This means we require two calibration units calibrating two pixels in each programming cycle. This shows that it is feasible to implement this calibration system with very low cost. The frequency of calibration can be reduced automatically as the display ages, since shifts in characteristics will become slower as the time progresses. In addition, the calibration can be performed at multiple brightness levels for one pixel to achieve higher accuracy.

Figure 2 shows an architectural implementat'ron of such calibration system showing the Calibration Scheduler and Memory 307 and Compensation Memory 308. It also shows Display Array 300, Pixels 301, Gate Lines 302, Data Lines 303, and Power Lines 304.
The Gate Lines 302 are connected to the Gate Driver 305 and Power Lines to the Power Supply 306. In each programming cycle a column of pixels are selected. The Digital Data Input is added to the ~V
compensation voltage value that is stored in Compensation Memory 308 for each pixel by the Adder 309 and the corresponding voltage is applied to the Data Lines 303 by the Voltage Data Driver 310. When the Calibration Scheduler and Memory 307 has enabled the Normal Operation for that data line, switch 311 is activated and the voltage is directly applied to the pixel. When the Calibration Scheduler and Memory 307 has enabled the Calibration Mode for that data line, switch 312 is activated and the voltage is applied to the pixel through the accurate resistor R 313.
The voltage drop across the resistor 313 at the final stages of the programming time is measured by the voltage sensor 314 and converted to digital data by AID 316. The resulting value of the voltage drop is proportional to the current flowing through the pixel if a current programmed pixel circuit is present. This value is compared with the Comparator 316 to the expected value obtained from the Digital Data Input by the translator 317. The difference between the expected and measured value is stored in the compensation memory 308 and will be used for subsequent programming use.
[1] US Patent No. 6,594,606

Claims

CA002490860A 2004-12-15 2004-12-15 Real-time calibration scheduling method and algorithm for amoled displays Abandoned CA2490860A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA002490860A CA2490860A1 (en) 2004-12-15 2004-12-15 Real-time calibration scheduling method and algorithm for amoled displays

Applications Claiming Priority (24)

Application Number Priority Date Filing Date Title
CA002490860A CA2490860A1 (en) 2004-12-15 2004-12-15 Real-time calibration scheduling method and algorithm for amoled displays
PCT/CA2005/001897 WO2006063448A1 (en) 2004-12-15 2005-12-15 Method and system for programming, calibrating and driving a light emitting device display
JP2007545796A JP5128287B2 (en) 2004-12-15 2005-12-15 Method and system for performing real-time calibration for display arrays
EP11168677.0A EP2383720B1 (en) 2004-12-15 2005-12-15 Method and system for programming, calibrating and driving a light emitting device display
KR1020077016146A KR20070101275A (en) 2004-12-15 2005-12-15 Method and system for programming, calibrating and driving a light emitting device display
CA002590366A CA2590366C (en) 2004-12-15 2005-12-15 Method and system for programming, calibrating and driving a light emitting device display
EP13187593.2A EP2688058A3 (en) 2004-12-15 2005-12-15 Method and system for programming, calibrating and driving a light emitting device display
EP05819617.1A EP1836697B1 (en) 2004-12-15 2005-12-15 Method and system for programming, calibrating and driving a light emitting device display
US11/304,162 US7619597B2 (en) 2004-12-15 2005-12-15 Method and system for programming, calibrating and driving a light emitting device display
CA002526782A CA2526782C (en) 2004-12-15 2005-12-15 Method and system for programming, calibrating and driving a light emitting device display
TW094144535A TWI402790B (en) 2004-12-15 2005-12-15 Method and system for programming, calibrating and driving a light emitting device display
CN 200580048020 CN101116129B (en) 2004-12-15 2005-12-15 Method and system for programming, calibrating and driving a light emitting device display
US12/571,968 US8259044B2 (en) 2004-12-15 2009-10-01 Method and system for programming, calibrating and driving a light emitting device display
JP2012045806A JP5822759B2 (en) 2004-12-15 2012-03-01 System for display array
US13/568,784 US8736524B2 (en) 2004-12-15 2012-08-07 Method and system for programming, calibrating and driving a light emitting device display
US14/157,031 US8994625B2 (en) 2004-12-15 2014-01-16 Method and system for programming, calibrating and driving a light emitting device display
US14/175,493 US8816946B2 (en) 2004-12-15 2014-02-07 Method and system for programming, calibrating and driving a light emitting device display
US14/253,422 US9275579B2 (en) 2004-12-15 2014-04-15 System and methods for extraction of threshold and mobility parameters in AMOLED displays
US14/261,755 US9280933B2 (en) 2004-12-15 2014-04-25 System and methods for extraction of threshold and mobility parameters in AMOLED displays
JP2014240307A JP6086893B2 (en) 2004-12-15 2014-11-27 Method for extracting circuit parameters
US14/643,584 US9970964B2 (en) 2004-12-15 2015-03-10 Method and system for programming, calibrating and driving a light emitting device display
US14/738,393 US10012678B2 (en) 2004-12-15 2015-06-12 Method and system for programming, calibrating and/or compensating, and driving an LED display
US14/816,817 US10013907B2 (en) 2004-12-15 2015-08-03 Method and system for programming, calibrating and/or compensating, and driving an LED display
US16/005,177 US20180301077A1 (en) 2004-12-15 2018-06-11 Method and system for programming, calibrating and/or compensating, and driving an led display

Publications (1)

Publication Number Publication Date
CA2490860A1 true CA2490860A1 (en) 2006-06-15

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CA002490860A Abandoned CA2490860A1 (en) 2004-12-15 2004-12-15 Real-time calibration scheduling method and algorithm for amoled displays

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CA (1) CA2490860A1 (en)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009110132A1 (en) * 2008-03-06 2009-09-11 富士電機ホールディングス株式会社 Active matrix display device
US9886899B2 (en) 2011-05-17 2018-02-06 Ignis Innovation Inc. Pixel Circuits for AMOLED displays
US9721505B2 (en) 2013-03-08 2017-08-01 Ignis Innovation Inc. Pixel circuits for AMOLED displays
CN105960670B (en) * 2013-12-05 2017-11-10 伊格尼斯创新公司 The pixel circuit and method for extracting and providing the compensation circuit parameters pixels
JP5893550B2 (en) * 2012-04-12 2016-03-23 キヤノン株式会社 Imaging apparatus and imaging system
JP5955073B2 (en) * 2012-04-23 2016-07-20 キヤノン株式会社 Display device and driving method of display device
US8922544B2 (en) * 2012-05-23 2014-12-30 Ignis Innovation Inc. Display systems with compensation for line propagation delay
KR20140083185A (en) * 2012-12-24 2014-07-04 엘지디스플레이 주식회사 Organic light emitting display device and method for driving the same
US9351368B2 (en) * 2013-03-08 2016-05-24 Ignis Innovation Inc. Pixel circuits for AMOLED displays
US20140368491A1 (en) 2013-03-08 2014-12-18 Ignis Innovation Inc. Pixel circuits for amoled displays
US9430968B2 (en) * 2013-06-27 2016-08-30 Sharp Kabushiki Kaisha Display device and drive method for same
KR20160041097A (en) 2014-10-06 2016-04-18 엘지디스플레이 주식회사 Organic electro luminescent display device and transitor structure for display device
KR20160078749A (en) * 2014-12-24 2016-07-05 엘지디스플레이 주식회사 Organic light emitting diode display device and method of sensing device characteristic
CA2894717A1 (en) 2015-06-19 2016-12-19 Ignis Innovation Inc. Optoelectronic device characterization in array with shared sense line

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US6259424B1 (en) 1998-03-04 2001-07-10 Victor Company Of Japan, Ltd. Display matrix substrate, production method of the same and display matrix circuit
US6738035B1 (en) 1997-09-22 2004-05-18 Nongqiang Fan Active matrix LCD based on diode switches and methods of improving display uniformity of same
US6690344B1 (en) 1999-05-14 2004-02-10 Ngk Insulators, Ltd. Method and apparatus for driving device and display
US6414661B1 (en) 2000-02-22 2002-07-02 Sarnoff Corporation Method and apparatus for calibrating display devices and automatically compensating for loss in their efficiency over time

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CN101116129B (en) 2011-03-30

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